The human heart is a pump—a complex and critical pump. As with any pump, the heart can become clogged and wear out over time. When wear and damage to the heart become sufficiently serious, the owner of the heart is said to have suffered severe heart failure. In such a situation, it is often necessary for the person to receive mechanical assistance for the heart or to receive a heart transplant. Where the person is scheduled to receive a transplant, mechanical assistance may be a choice of therapy until a donor heart is available.
Blood pumps are commonly used to provide mechanical assistance to the left ventricle of the heart. Ventricular assistance may be provided by an implantable pump that is connected in parallel with the person's cardiovascular system. A controller that is external to the body may regulate the pump. Additionally, the controller and the pump may require power from a source such as one or more batteries. For a patient to maintain mobility, such external components can be carried by the patient.